Tilting mechanism for spray guns



Sept. 4, 1962 H. E. M ARTHUR ETAL 3,052,212

TILTING MECHANISM FOR SPRAY GUNS Filed Dec. 8, 1.958 3 Sheets-Sheet 1 INVENTORS HAMILTON E. MAcARTHUR JOSEPH J. KERTZ ATTORNEYS Se t. 4, 1962 H. E. M ARTHUR ETAL 3,052,212

TILTING MECHANISM FOR SPRAY GUNS Filed Dec. 8, 1958 3 Sheets-Sheet 2 a 58 s l 6| INVENTORS HAMILTON E, MACARTHUR BYJOSEPH J. KERTZ WWvM ATTORNEYS Sept. 4, 1962 H. E. M ARTHUR ETAL 3,052,212

TILTING MECHANISM FOR SPRAY GUNS 3 Sheets-Sheet 5 Filed Dec. 8, 1958 JOSEPH J. KERTZ WWYM ATTORNEYS INVENTORS 171 g. E HAMILTON E. MAcARTHUR United States Patent O 3,052,212 TllLTlNG MECHANRSM FOR SPRAY GUNS Hamilton E. MacArthur and Joseph J. Kertz, Toledo, Ohio, assignors to Conforming Matrix Corporation, Toledo, Ohio, a corporation of Ohio Filed Dec. 8, 1%8, Ser. No. 778,741 Claims. (Cl. 118--323) This invention relates to spray painting apparatus of the type which paints articles by means of spray guns and masking shields that confine the paint accurately to desired patterns.

The painting apparatus of the invention is an improvement over the apparatus which is shown and described in copending United States application Serial No. 778,674 filed December 8, 1958, in the names of C. G. Martin and L. T. McHue. The apparatus that is disclosed in the copending application is exemplified by a double fixture painting machine. One of the fixtures automatically moves an articles to be coated from a loading position into juxtaposition with a form-fitting, stencil-like mask which article is sprayed automatically while an attendant removes a coated article from the other fixture while it is in its loading position and replaces it with an article to be coated. The coating compound is applied by means of a plurality of sprayers which are reciprocated in paths adjacent the masks. Optionally, the sprayers may be rocked automatically at the ends of the paths in which they are reciprocated so that they are oriented to direct their spray onto all of the surfaces of irregularly shaped articles.

The sprayers, as disclosed in the application, are mounted in pairs each on the lower end of a lever which is fulcrumed an appreciable distance overhead on a reciprocable carriage. Rocking of the lever about its fulcrum rocks the sprayers carried thereby. This arrangement is unsatisfactory in that space is wasted at the ends of the paths in which each set of sprayers is reciprocated, because each one of the levers is tilted toward the ends of its path while it approaches either end and, thus, requires more space than if it were reciprocated while it was in a vertical or non-tilted position. Hence, the painting machine is relatively large and, thus, wastes floor space.

It is, accordingly, the principal object of this invention to provide, in apparatus for spraying a coating compound, improved means for tilting or rocking a sprayer so that it directs coating compound onto all of the surface of an irregularly shaped article.

Another object is to provide, in apparatus for spraying a coating compound by means of a reciprocating sprayer, means for so tilting or rocking such sprayer that no space in the apparatus is wasted because of such tilting or rocking.

A further object is to provide compact apparatus for spraying a coating compound by means of a reciprocable and rockable sprayer.

Still another object is to provide an improved spray gun tilting mechanism.

Other objects and advantages will be apparent from the following description in which reference is had to the accompanying drawings.

According to the invention, compact apparatus is provided for applying coating compounds to articles by means of a reciprocating sprayer. The apparatus features a tilting mechanism which so tilts or rocks the sprayer that no space in the apparatus is wasted because of such tilting or rocking. The tilting mechanism includes a sleeve which is carried in a selectively adjustable position on a reciprocable carriage, the sleeve extending toward an article to be coated. A shaft, to which the sprayer is secured, is mounted for rotation on the sleeve which shaft "ayeszaiz is turned by means of a rack that is slidably mounted within the sleeve and that meshes with a pinion on the shaft. Means are provided for reciprocating the carriage to move the sprayer in a path adjacent the article to be coated, the carriage carrying means for driving the rack to tilt the sprayer relative to the article so that the sprayer directs coating compound onto all of the surface of an irregularly shaped article. Since the only part of the tilting mechanism which is tilted is the shaft, the length of the path in which the sprayer is reciprocated is kept to a minimum.

A preferred embodiment is illustrated in the accompanying drawings.

In the drawings:

,FIG. I is a view in perspective of a painting machine embodying the invention;

FIG. II is an elevational view of tilting mechanism for a pair of the spray guns which is shown in FIG. I and of the reciprocable support for such mechanism, a portion being shown in vertical section; and

'FIG. III is an elevational :view of the device shown in FIG. II as seen from a position to the left of the device as shown in FIG. II, a portion being shown in vertical section.

These specific figures are intended merely to illustrate the invention but not necessarily to limit its scope.

The painting machine, which is shown and described generally in the hereinbefore referred to application Serial No. 778,674, includes a cabinet 1 partially enclosing a left hand application station or area 2 and a right hand application station or area 3. The application areas 2 and 3 are defined by a rear wall 4, side walls 5, and the top of a work table 6, a partition 7 separating the areas.

Articles to which coating compounds are to be applied are supported in the application areas 2 and 3 on work holding means 8. Specifically, such articles as shown for the purpose of illustration are toy automobiles 9 one of which can be seen in the right hand application area 3. Each of the work holding means 8 includes a work holder 10 which is formed by being cast inside a toy automobile 9 and then finished until the automobile is easy to fit over the holder 10 and is easy to remove, but which has a tight enough fit to hold the automobile securely during the various operations of the machine. The cast part of such work holder 10 is secured to a base 11 which is secured in turn on an adapter 12 atop a piston rod 13. Each of the piston rods 13 is an operative part of an air cylinder 14 which is secured in a vertical position to the underneath side of the work table 6 with its piston extending through the table into its application area. Access to the cylinders 14, there being one below each of the application areas 2 and 3, is obtained through an opening in an end of the cabinet 1 that normally is closed by a door 15. Part of the cabinet 1 below the application area 2 is broken away to reveal one of the cylinders 14 and its adjuncts.

If it is desired to apply decorating compound to only certain patterns on the articles, the cabinet 1 is provided with masking shields, i.e., form-fitting, stencil-like masks 16, detachably mounted on adjustable mask holders 17, there being a mask 16 located directly above each of the work holders 10. Each one of the masks 16 has an opening 18 which, when an automobile 9 is fitted within the mask as shown in the left hand application 2, permits coating compound to be sprayed through the mask onto the roof of the automobile, the rest of the automobile being masked ofiF. The stroke of each of the piston rods 13 is such that in the retracted position of the rod as shown in the right hand application area 3 the work holder 10 is in a convenient position to be unloaded and/or loaded and in the extended position of the rod as shown in the left hand application area 2 the work 3 holder 10 holds the article 9 to be coated in the mask 16, i.e., in juxtaposition with the mask.

Each of the mask holders 17 includes a base 19' secured to the top of the work table 6 and a pair of legs 20 secured in turn to the base 19. A horizontally grooved guide 21 is mounted atop each of the legs 20 and a latch bar 22 is secured to the guides 21 in a position parallel to the base 19. The grooved guides 21 are adapted to receive the side edges of the mask 16 which is slid into the mask holder 17 until its back edge is against the latch bar 22. Pins 23 are thrust through aligned holes in the mask holder and the mask 16 to hold the mask in place.

In the general operation of the machine, the attendant unloads the article 9 which has been painted from that one of the work holders 10 which is in its loading (retracted) position and replaces it with an article to be painted. 'l he piston rods 13 then are caused to reverse their positions, the newly loaded one of the piston rods advancing its work holder 10 along with the article 9 to be painted thereon into its mask 16 and the other one of the piston rods lowering its work holder 10 along with the freshly painted article 9 thereon into its unloading position. As shown in FIG. I, the left hand one of the piston rods 13 is extended and has lifted the article 9 into a juxtaposed position relative to its mask 16 ready to be painted and the right hand one of the piston rods 13 is retracted and has lowered the freshly painted article 9 into unloading position.

When the article 9 is positioned in its mask 16 ready to be painted, it is sprayed by means of a pair of conventional spray guns 24 in each of the application areas 2 and 3. Each pair of guns 24 is secured to a shaft 25 that is pivotally mounted on the lower end of a sleeve 26 which is stationarily mounted in a selectively adjustable position on a carriage 27 only the bottom part of one of which is visible in FIG. I, the sleeve 26 extending toward the article to be sprayed. The carriages 27 are hidden behind doors 28 in FIG. I, two of such doors being shown shut and one being shown open. The spray guns 24 are so positioned on the shafts 25 that each one directs its spray toward the surface to be painted and so that the spray from each pair completely covers the surface it is spraying upon. Suitable exhaust equipment filters and discharges fumes through a stack which communicates with discharge ports 29 in the rear wall 4 of the cabinet 1 to maintain an atmosphere free from coating or painting compounds.

The carriages 27 are slidably mounted on a pair of track rods 30 which extend the full width of the cabinet 1 and which are suitably supported at the side wall and are large enough to form a rigid track for the two carriages 27 to be reciprocated upon. Each of the carriages 27 includes a horizontal bottom plate 31 and a pair of vertical side plates 32 extending upwardly therefrom in which bushings 33 that receive the track rods 30 are mounted. A pair of back and front plates 34 is attached to the plates 31 and 32 and each of these supports an arm 35 one of which is secured to the lower flight of one of a pair of continuous chains 36 and the other one of which is secured to the lower flight of the other one of the continuous chains 36, washer members 37 and bolts 38 serving to connect the arms 35 and the chains 36. Each of the continuous chains 36 extends between idler sprockets 39 one of which is shown in FIG. I, there being a pair of sprockets 39 at each of the side walls 5 of the cabinet 1. Each of the pairs of sprockets 39 is mounted on a shaft 40 which is journaled at its ends in bearings 41 atop blocks 42 that are on a horizontal shelf 43 of the cabinet 1. The piston rod of a cylinder (not shown) is operatively connected to the upper flights of the continuous chains 36 so that the piston rod and the chains move together as one. The piston rod and the cylinder together with its operative connection are shown and described in detail in the hereinbefore referred to application Serial No. 778,674. Movement of the piston rod to the left as viewed in FIG. I (extended position) moves the upper flights of the continuous chains 36 to the left and the lower flights of the chains 36 to the right and, therefore, both of the carriages 27 to the right. Hence, the spray guns 24 are reciprocated in paths adjacent the masks 16. As shown in FIG. I, the carriages 27 are in non-spraying positions at the left hand sides of their respective application areas 2 and 3 of the cabinet 1.

If instead of painting the roofs of the toy automobiles 9, the bodies of such automobiles were being painted, it is necessary to tilt the spray guns 24 at each end of the paths in which the two sets of spray guns are reciprocated toward the masks 16 so that as the guns are reciprocated the spray impinges upon all of the irregular surfaces such as the partially hidden spots underneath the hoods over the headlights. This is accomplished, without wasting space because of the tilting, by means of the tilting mechanism of the invention which is shown in detail in FIGS. II and III.

The tilting mechanisms for the spray guns 24 in the application areas 2 and 3 are identical and, therefore, only one of the mechanisms is described in connection with FIGS. II and III. The sleeve 26 extends through an opening in the horizontal bottom plate 31 of the carriage 27 and is supported by means of a split collar 44 fixed to the bottom of the plate 31. When a screw '45 which clamps the collar 44 on the sleeve is loosened, the sleeve 26 can be moved up or down in the collar to adjust the space between the spray guns and the article to be sprayed, the screw 45 being tightened to secure the sleeve in its adjusted position.

A shaft journal and gear case 46- is secured to the lower end of the sleeve 26 by means of four screws 47; it comprises a housing 43 into the top of which the screws 47 are threaded and which has a gear chamber 49 opening to the right as viewed in FIG. III. The chamber 49 is closed by means of a cap 53 which is secured to the housing 48 by three screws 51. When the housing 48 and the cap 50 are assembled, a horizontal hole in the housing is aligned with a horizontal hole in the cap, flanged bushings 52 in the aligned holes being spaced from each other as shown in FIG. III.

The shaft 25 is received by the bushings 52 and is provided with a keyway 53 which is juxtaposed to a keyway 54- in a pinion 55 on the shaft, a key 56 in the keyways connecting the pinion and the shaft so that they turn as one. The pinion 55 is located axially on the shaft 25 between the spaced flanges of the bushings 52 and is free to turn on the bearing surfaces of the flanges within the gear chamber 49. A vertical hole 57 in the housing 48 communicates with the chamber 49 in the housing 48 and is aligned with a hole 58 that extends vertically all of the Way through the sleeve 26.

A rack 59 in the form of a rod in which rack teeth 60 are cut is received in the hole 58 through the sleeve 26, such teeth 66 being meshed with the pinion 55. The rack 59 is axially slidable within the sleeve 26 on the bearing surfaces of a pair of bushings 61 located one at each end of the sleeve.

A collar 62, which is like the collar 44, is clamped on the upper end of the sleeve 26 in a location above the horizontal bottom plate 31 of the carriage 27 and supports a horizontal plate 63. A bifurcated bracket 64 is secured by means of screws 65 to the plate 63 and functions to pivotally support a bell crank 66 at 67 between its bifurcations 68. A horizontal pin 69 which extends between bifurcations 72 atop the rack 59 is received in a notch 70 at the end of one of the arms of the bell crank 66 and functions to operatively connect the rack 59 to the bell crank 66. Clock-wise movement of the bell crank 66 about its pivot 67 as viewed in FIG. II causes the rack 59 to be slid upwardly in the sleeve 26 and counterclockwise movement of the bell crank 66 causes the rack to be driven downwardly.

An air cylinder 71 is fixed to the plate 63 and it has a piston rod 73 an exposed end of which extends through a hole 7-4 in the bracket 64 and bears against an abutment surface 75 at the end of the other one of the arms of the bell crank 66. Springs 76 extend between pins 77 and 78 extending on either side of the bracket 64 and the bell crank 66, respectively, and urge the abutment surface 75 of the bell crank continuously against the end of the piston rod 73. When compressed air drives the piston rod 73 to the left as viewed in FIG. II, i.e., to its extended position, it pivots the bell crank 66 in a clockwise direction about the pivot 67 in opposition to the springs 76 to its position indicated by broken lines in FIG. II. When pressure of the compressed air is relaxed, the springs 76 pivot the bell crank counterclockwise about the pivot 67 to its position also indicated in FIG. II and return the piston rod 73 to its retracted position.

In operation, one of the work holder piston rods 13 is extended and the other one of the work holder piston rods 13 is retracted and the two sets of spray guns 24 are reciprocated. The set of guns 24 which corresponds to the extended one of the work holder piston rods 13 sprays on both the forward and return strokes, the spray guns rocking or tilting at the ends of the paths in which they are reciprocated. This cycle of operation is described in detail in the hereinbefore referred to application Serial No. 778,674. However, instead of rocking the entire gun supports which wastes space at the ends of the paths in which each set of spray guns is reciprocated as is done in the machine shown and disclosed in the copending application, only the shafts 25 of the gun supports in the tilting mechanism of the invention are rocked. Hence, no space in the improved machine is wasted because of such tilting, the sleeves 26 of the gun supports being held vertically at all times to keep the lengths of the paths in which the spray guns are reciprocated a mini-mum. Admission of air to the cylinders 71 which are carried by the carriages 27 causes the bell cranks 66 to assume their positions illustrated by the upper broken lines in FIG. II. This moves the racks 59 upwardly driving the pinions 55 and the shafts 25 connected thereto to pivot the spray guns 24 about the axes of the shafts. Relaxation of the air pressure in the cylinders 71 permits the springs 76 to move the bell cranks 66 into their positions illustrated by the lower broken lines in FIG. II. This turns the pinions 55 and the shafts 25 in the reverse direction. After unloading the retracted one of the work holders, the cycle is repeated. The work holder piston rods reverse their positions, again the two sets of guns are reciprocated and tilted at the ends of the paths in which they are reciprocated, and again the set of guns which corresponds to the extended one of the work holder piston rods sprays on both the forward and return strokes.

Various modifications may be made in specific details of construction without departing from the spirit and scope of the invention.

Having described the invention, we claim:

1. In apparatus for applying coating compounds to articles, in combination, a reciprocable carriage, a sleeve carried by the carriage, a shaft mounted for rotation on the sleeve, a spray gun secured to the shaft, a pinion on the shaft, a rack slidably mounted within the sleeve and meshed with the pinion, and means for driving the rack in order to pivot the spray gun about the axis of the shaft.

2. In apparatus for applying coating compounds to articles, in combination, a reciprocable carriage, a sleeve carried by the carriage, a shaft mounted for rotation on the sleeve, a spray gun secured to the shaft, a pinion on the shaft, a rack slidably mounted within the sleeve and meshed with the pinion, means carried by the carriage for driving the rack in order to pivot the spray gun about the axis of the shaft, and adjustment means for the shaft for locating the axis of the shaft relative to the carriage.

3. In apparatus for applying coating compounds to articles, in combination, a reciprocable carriage, a sleeve carried by the carriage, a shaft mounted for rotation on the sleeve, a spray gun secured to the shaft, a pinion on the shaft, a rack slidably mounted within the sleeve and meshed with the pinion, a bell crank fulcrumed on the carriage and operatively connected to the rack, and means for moving the bell crank about its fulcrum, whereby the rack is slid in the sleeve to pivot the spray gun about the axis of the shaft.

4. In apparatus for applying coating compounds to articles, in combination, a reciprocable carriage, a sleeve carried by the carriage, a shaft mounted for rotation on the sleeve, a spray gun secured to the shaft, a pinion on the shaft, a rack slidably mounted within the sleeve and meshed with the pinion, a bell crank fulcrumed on the carriage and operatively connected to the rack, means for moving the bell crank about its fulcrum, whereby the rack is slid in the sleeve to pivot the spray gun about the axis of the shaft, and adjustment means for the shaft for locating the axis of the shaft relative to the carriage.

5. In apparatus for applying coating compounds to articles, in combination, a reciprocable carriage, a sleeve that is carried by the carriage and that is stationary rela tive thereto, a spray gun, means carried by the sleeve for pivotally mounting the spray gun, and means within the sleeve for pivoting the spray gun.

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